# How do you write the equation in point slope form given Point: (1, 9); Slope: 5?

Mar 4, 2016

$y = 5 x + 4$

#### Explanation:

To begin, you're going to want to find your $y$-intercept (or $b$). To do this, you have to substitute your point $\left(1 , 9\right)$ into an equation. Those two points represent $x$ $\left(1\right)$ and $y$ $\left(9\right)$. Like this:

$y = 5 x + b$

$9 = 5 \cdot 1 + b$

$9 = 5 + b$

$9 - 5 = b \implies b = 4$ (your $y$-intercept)

Now, since you already have your slope $\left(5\right)$, just plug everything into your final equation $\left(y = m x + b\right)$

$y = 5 x + 4$